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GEORGE HOPKINS AND JOHN A. STRAIGHT, OF ALBION, NEW YORK.

Letters Pate-nt No. 106,820, dated August 30, 1870; antedated August 26,1870.

LOW-WATER INDICATOR.

The Schedule referred to in these Letters Patent and makingpart of thelame oi'v one ot' the metals over the othershall cause a mo-` tion whichmay be communicated to a valve, such arrangement-being so far removedfrom saidgenerator, but so connected with the water therein that, whenthe water is suiciently high, the apparatus' will be in contact withwater cooler than that in the generator, so as to prevent the expansionof the metals, but'when the' wateriu the generatoI shall fall below aproper height, the steam will enter and corne in contact with themetals, cansing'their expansion.

The second part ot' our invention relates to the combination of apressure-alarm with the above device.

The object of this invention is to provdean apparatns which is to beconnected witlta steam-generator at a given line, which shall alarmwhenever the water in theA generator passes below said line, and also togive al1-alarm at al given pressure of steam.

Description of the Accolnqumy/ing Drawing. Figure l is a frontelevation.

Figure 2 is an elevation showing the parts. in the.

rear of fig. 1. v

Figure 3 shows the internal construction.

Figure 4 is a vertical section, taken on the line xx, drawn throughfigs. 1, 2, and 3.

General Description.

A is a case, containing compound ring B, of brass and iron, or of othermetals of diiferent expansibilities, attached to the case A at G.

rlhe ring B is separated, leaving the cud D free to move.

E-is a lever, connected with the ring B at D, and is ixed to the shafta.

rJhe shaft a passes outthrough the stuing-box b, and is provided withthe lever F.

G is a safety-valve, attached to the case A, having the lever Hconnected with the valve-lever, and passes down so as to engage with thelever F.

c is a set-screw in the lever F.

I is a passage leading from the safety-valve G to the steam-room of thegenerator.

J is a whistle, connected with thevalve G, so as to take the steam whichescapes it.`

K is a passage, communicating'with the water-space of the generator.

As long as the water iu the generator covers the end of the pipe whichconuects'it with-the case A, the water in the case will remaincomparatively cool. When the water in the generator drops below the cudof said pipe, the water passes outof the case A,

and the steam enters, heating the compound ring B,

and the brass, expanding more than the iron, causing a motion ot thefree end D, which motion is communicated to the valve through the leversE, F, and H, and the steam is permitted to escape through the whistle J,thereby causing an alarm.

In tig. 3 the dotted lines show the manner of attaching the valve Ldirectly to the compound ring B..

.lf it is desired, the valve may be retained to its seat by the pressureof steam -in lieu oi' the weighted lever.

Claims.

\Ve claim as our invention-f 1 The compound ring B, or its equivalent,when so far removed from a steamfenerator, but so constructed with thewater therein that, when the water is suciently high, the ring shall bein contact with water cooler than the water in the generator; but when'the water in the generator shall fall below a proper'height the steamwill come in contact with the compound ring B, and cause it to expand,for the purpose substantially as described. f

2. The combination of the compound ring B, the safety=valve*G, andtheaccompanyimir devices, substantially as and for the purpose hereinbeforeset forth.

, GEO. M. HOPKINS,

JOHN A. STRAIGHT. Witnesses:

- WiLLIAM DANFOBTH,

W. O. HAYES.

